全文获取类型
收费全文 | 190篇 |
免费 | 7篇 |
国内免费 | 42篇 |
专业分类
安全科学 | 13篇 |
废物处理 | 17篇 |
环保管理 | 11篇 |
综合类 | 56篇 |
基础理论 | 32篇 |
污染及防治 | 81篇 |
评价与监测 | 18篇 |
社会与环境 | 6篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 11篇 |
2017年 | 13篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 5篇 |
2013年 | 22篇 |
2012年 | 10篇 |
2011年 | 19篇 |
2010年 | 9篇 |
2009年 | 10篇 |
2008年 | 17篇 |
2007年 | 12篇 |
2006年 | 6篇 |
2005年 | 13篇 |
2004年 | 2篇 |
2003年 | 11篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有239条查询结果,搜索用时 31 毫秒
81.
Characterization and reactivity of natural manganese ore catalysts in the selective catalytic oxidation of ammonia to nitrogen 总被引:3,自引:0,他引:3
Natural manganese ore (NMO) catalysts were characterized and tested in the selective catalytic oxidation of ammonia to nitrogen oxides under dilute conditions. Also, the oxidation of ammonia (NH(3)) was carried out using pure MnO(2), Mn(2)O(3) for comparing with the activity. It is found that the activity of NMO was similar to that of MnO(2) at low temperature below 150 degrees C but above this temperature, the activity of these catalysts showed the difference. In the course of NH(3) oxidation, N(2), NO, N(2)O and H(2)O were produced. But the quantity of NO(2) produced in this experiment was negligible. At temperature below 250 degrees C, selectivity into N(2) from NH(3) oxidation was in the order, NMO > MnO(2) > Mn(2)O(3). This is the reverse of activity of these manganese oxides. Also the characterization of NH(3) oxidation was proposed and supported by the effect of space velocity, inlet O(2) and NH(3) concentration. The increase of space velocity remarkably influenced not only the conversion but also selectivity into N(2). The higher the reaction temperature was, the higher the effect of inlet O(2) and NH(3) concentration on the reaction rate was. By introducing NO during NH(3) oxidation reaction, the possibility of NMO as selective catalytic reduction catalyst at low temperature was studied and showed positive results. 相似文献
82.
The effects of initial trichloroethylene (TCE) concentration, recirculating liquid flow rate and gas velocity on photodegradation of TCE have been determined in an internally circulating slurry bubble column reactor (0.15m-ID x 0.85 m-high). Titanium dioxide (TiO2) powder was employed as a photocatalyst and the optimum loading of TiO2 in the present system is found to be approximately 0.2 wt%. The stripping fraction of TCE by air flow increases but photodegradation fraction of TCE decreases with increasing the initial TCE concentration, recirculating liquid flow rate and gas velocity. The average removal efficiency of TCE is found to be approximately 97% in an internally circulating slurry bubble column reactor. 相似文献
83.
Trichloroethylene degradation by photocatalysis in annular flow and annulus fluidized bed photoreactors 总被引:7,自引:0,他引:7
The effects of trichloroethylene (TCE) gas flow rate, relative humidity, TiO(2) film thickness, and UV light intensity on photodegradation of TCE have been determined in an annular flow type photoreactor. Phosgene and dichloroacetyl chloride formation could be controlled as a function of TCE gas flow rate and photodegradation of TCE decreased with increasing relative humidity. The optimum thickness of TiO(2) film was found to be approximately 5 mum and the photocatalytic reaction rate of TCE increased with square root of UV light intensity. In addition, the effects of the initial TCE concentration, phase holdup ratio of gas and solid phases (epsilon(g)/epsilon(s)), CuO loading on the photodegradation of TCE have been determined in an annulus fluidized bed photoreactor. The TCE photodegradation decreased with increasing the initial TCE concentration. The optimum conditions of the phase holdup ratio (epsilon(g)/epsilon(s)) and CuO wt.% for the maximum photodegradation of TCE was found to be 2.1 and 1.1 wt.%, respectively. Therefore, an annulus fluidized bed photoreactor is an effective tool for TCE degradation over TiO(2)/silica gel with efficient utilization of photon energy. 相似文献
84.
85.
Dr. Lilian M. Lopes Sang Choon Cha Edécio Armbruster De Moraes Marcelo Zugaib 《黑龙江环境通报》1995,15(2):183-185
Fetal echocardiography was performed during the third trimester in a normal primigravida. The fetal heart was severely affected with the typical cardiac manifestations of Marfan syndrome. The medical history of the father was investigated and a mild form of the syndrome was diagnosed. The neonate died at 2 months of age of congestive heart failure. 相似文献
86.
Liu Xinji Zhang Jingjing Sang Yanru Liu Kaiyong Zhu Yitian Yang Linsheng Wang Sufang Sheng Jie Wang Qunan Zhang Dongmei Cao Hongjuan Tao Fangbiao 《Environmental science and pollution research international》2021,28(21):26794-26806
Environmental Science and Pollution Research - To examine the associations between urinary antibiotics from various sources and depression in the elderly using the biomonitoring method. In the... 相似文献
87.
NO removal by reducing agents and additives in the selective non-catalytic reduction (SNCR) process 总被引:2,自引:0,他引:2
The effect of the additives on the selective non-catalytic reduction (SNCR) reaction has been determined in a three-stage laboratory scale reactor. The optimum reaction temperature is lowered and the reaction temperature window is widened with increasing concentrations of the gas additives (CO, CH4). The optimum reaction temperature is lowered and the maximum NO removal efficiency decreases with increasing the concentration of alcohol additives (CH3OH, C2H5OH). The addition of phenol lowers the optimum reaction temperature about 100-150 degrees C similar to that of the toluene addition. The volatile organic compounds (VOCs: C6H5OH, C7H8) can be utilized in the SNCR process to enhance NO reduction and removed at the same time. A previously proposed simple kinetic model can successfully apply the NO reduction by NH3 and the present additives. 相似文献
88.
Application of eggshell waste for the immobilization of cadmium and lead in a contaminated soil 总被引:2,自引:0,他引:2
Ok YS Lee SS Jeon WT Oh SE Usman AR Moon DH 《Environmental geochemistry and health》2011,33(Z1):31-39
Liming materials have been used to immobilize heavy metals in contaminated soils. However, no studies have evaluated the use of eggshell waste as a source of calcium carbonate (CaCO?) to immobilize both cadmium (Cd) and lead (Pb) in soils. This study was conducted to evaluate the effectiveness of eggshell waste on the immobilization of Cd and Pb and to determine the metal availability following various single extraction techniques. Incubation experiments were conducted by mixing 0-5% powdered eggshell waste and curing the soil (1,246 mg Pb kg?1 soil and 17 mg Cd kg?1 soil) for 30 days. Five extractants, 0.01 M calcium chloride (CaCl?), 1 M CaCl?, 0.1 M hydrochloric acid (HCl), 0.43 M acetic acid (CH?COOH), and 0.05 M ethylendiaminetetraacetic acid (EDTA), were used to determine the extractability of Cd and Pb following treatments with CaCO? and eggshell waste. Generally, the extractability of Cd and Pb in the soils decreased in response to treatments with CaCO? and eggshell waste, regardless of extractant. Using CaCl? extraction, the lowest Cd concentration was achieved upon both CaCO? and eggshell waste treatments, while the lowest Pb concentration was observed using HCl extraction. The highest amount of immobilized Cd and Pb was extracted by CH?COOH or EDTA in soils treated with CaCO? and eggshell waste, indicating that remobilization of Cd and Pb may occur under acidic conditions. Based on the findings obtained, eggshell waste can be used as an alternative to CaCO? for the immobilization of heavy metals in soils. 相似文献
89.
Jeong-Ho HanHema K. Kumar Jae Hoon LeeChang-Ik Zhang Se-Wha KimJung-Ho Lee Sang Don KimKwang-Guk An 《Ecological modelling》2011,222(19):3457-3472
The objective of this study was to describe the trophic structure and energy flow in a lentic ecosystem in South Korea. Physicochemical water conditions were evaluated along with the reservoir ecosystem health using a multimetric IBI model. Nutrient analyses of the reservoir showed a nutrient rich and hypereutrophic system. Guild analysis revealed that tolerant and omnivorous species dominated the ecosystem. Tolerant fish, as a proportion of the number of individuals, were associated (R2 > 0.90, p < 0.01) with TN and TP, the key indicators of trophic state in lentic ecosystems. The mean Reservoir Ecosystem Health Assessment (REHA) score was 19.3 during the study, which was judged as in ‘fair to poor’ condition. A trophic analysis of the reservoir estimated by the ECOPATH model shows that most activity in terms of energy flow occurred in the lower part of the trophic web, where there was intensive use of primary producers as a food source. Consequently, of the 10 consumer groups, nine fell within trophic levels <2.8. Trophic levels (TL) estimated from the weighted average of prey trophic levels varied from 1.0 for phytoplankton, macrophytes, and detritus to 3.25 for the top predator, Pseudobagrus fulvidraco. Our integrated approach to trophic network analysis may provide a key tool for determining the effects of nutrient influx on energy flow pathways in lentic ecosystems. 相似文献
90.
Coking wastewater has caused serious health risk in coal-producing areas of China, however its toxic effects have not been well understood. The genotoxicity induced by coking wastewater on mice in vivo and its possible oxidative mechanisms were investigated via observing the induction of micronuclei in polychromatic erythrocytes of mouse bone marrow, and subsequently determining the antioxidative enzyme activities (superoxide dismutase Cu, Zn-SOD, Se-dependent glutathione peroxidase, and catalase), thiobarbituric acid reactive substance contents and protein carbonyl levels in brains and livers of mice. Results showed that the tested coking wastewater caused a significant increase of micronucleus frequencies in a concentration-dependent manner. Also, the sample increased lipid peroxidation and protein oxidation levels, which was accompanied by changes in antioxidative status. Interestingly, pre-treatment with an antioxidant (vitamin C) led to a statistical reduction in the micronucleus frequency caused by coking wastewater. This implies that coking wastewater induces evident genetic damage in mammalian cells, and exposure to polluted areas might pose a potential genotoxic risk to human beings; in the process, oxidative stress played a crucial role. 相似文献